But it's quite hard to find it! Maybe we can ask to add digamma in the title between parenthesis?

Fabien

2012/7/10 Damon McDougall <damon.mcdougall@gmail.com>

On Tue, Jul 10, 2012 at 08:57:24AM -0400, Benjamin Root wrote:

> On Tue, Jul 10, 2012 at 7:05 AM, Damon McDougall

> <damon.mcdougall@gmail.com>wrote:

>

> > On Tue, Jul 10, 2012 at 12:27:59PM +0200, Fabien Lafont wrote:

> >

> > > But It returns zero division error even when x is in ]0,1]

> >

> > I think it blows up at x = 0. What is the type of x in your usecase? Is

> > it an array? If x contains the element 0, you will get a zero

> > division error. You could try plotting the points explicitly:

> >

> Another problem might be the "1/2" part, which in python2.x would yield 0Wow, I can't believe I didn't spot that. Nice one.

> unless one does "from __future__ import division".

>

> Ben Root

I will update my answer according to Ben's astute observation:

from scipy import special

from pylab import *

x = linspace(0.5, 2.0, num=100, endpoint=True)

y = special.polygamma(0, 0.5 + 1.0/x)

plot(x, y)

show()

Thanks Ben.

--

Damon McDougall

http://damon-is-a-geek.com

B2.39

Mathematics Institute

University of Warwick

Coventry

West Midlands

CV4 7AL

United Kingdom